1. Field of the Invention
This invention relates to mesh networks, and particularly to systems, methods and computer products for establishing a mesh-network consisting of a wireless personal area network (WPAN) having a large number of nodes.
2. Description of Background
Integrated Wireless personal area networks (WPANs) convey information over relatively short distances using low-power radio transceivers based e.g. on the IEEE 802.15.4 standard. These radios are becoming cheap enough and sufficiently power efficient to be included in all kind of devices: cellular phones, PDAs, laptops, sensor devices, embedded devices, etc. In many situations it is desirable for one device to access a service provided by another device, either because the device itself does not support this service or because the device is in a state that the service is not available to itself. To reach the device offering an operational desired service the original device might have to initiate and traverse a wireless mesh-network.
Wireless mesh-networks are established using a large number of wireless devices called “nodes” that can relay messages and have messages relayed. The main features of such a mesh-network are that (1) the network can cover a large area that is typically much larger than the reach of the base technology; (2) the mesh-network is self-healing in the sense that it can cope with disappearing nodes by routing transmission around those “holes;” (3) the mesh-network topology lends itself particularly well to distributed/scattered sensor applications, where a large number of sensors are scattered over a large area.
The drawback to mesh networks is that they tend to consume a lot of power. This is power that could be saved for applications were the user is only interested in a certain subset of the wireless mesh-network and doesn't need to interact with the majority of the mesh-network. Some applications of mesh-networks, however, require the user to find (local) minima or maxima. For example, in a sensor mesh-network with temperature sensors scattered over an area we might only be interested in finding hot spots with high temperatures but not the hottest spot with the highest temperature. Therefore, the sensors in a “cold” part of the network are probably not of interest to the application, thus the application has to follow the temperature gradient towards the high temperature areas.
What is needed is a system and method that allows the whole of the mesh-network radios (e.g. RF) to be powered off when not in use. What is also needed is a mesh-network establishment that is driven by gradients and resource or service availability. This allows a lean mesh-network to be established that saves powers and reduces costs.